Self-assembled RNA nanocarrier-mediated chemotherapy combined with molecular targeting in the treatment of esophageal squamous cell carcinoma.

BACKGROUND: Esophageal cancer is the fifth most common cancer affecting men in China. The primary treatment options are surgery and traditional radio-chemotherapy; no effective targeted therapy exists yet. Self-assembled RNA nanocarriers are highly stable, easily functionally modified, and have weak off-tumor targeting effects. Thus, they are among the most preferred carriers for mediating the targeted delivery of anti-tumor drugs. miR-375 was found to be significantly down-regulated in esophageal squamous cell carcinoma (ESCC) tissues and its overexpression effectively inhibits the proliferation, migration, and invasion of ESCC cells. Moreover, epidermal growth factor receptor (EGFR) was overexpressed in ESCC cells, and accumulation of RNA nanoparticles in ESCC tumors was enhanced by EGFR-specific aptamer (EGFRapt) modification. RESULTS: Herein, a novel four-way junction RNA nanocarrier, 4WJ-EGFRapt-miR-375-PTX simultaneously loaded with miR-375, PTX and decorated with EGFRapt, was developed. In vitro analysis demonstrated that 4WJ-EGFRapt-miR-375-PTX possesses strong thermal and pH stabilities. EGFRapt decoration facilitated tumor cell endocytosis and promoted deep penetration into 3D-ESCC spheroids. Xenograft mouse model for ESCC confirmed that 4WJ-EGFRapt-miR-375-PTX was selectively distributed in tumor sites via EGFRapt-mediating active targeting and targeted co-delivery of miR-375 and PTX exhibited more effective therapeutic efficacy with low systemic toxicity. CONCLUSION: This strategy may provide a practical approach for targeted therapy of ESCC.

Overcoming Drug Resistance in Colon Cancer by Aptamer-Mediated Targeted Co-Delivery of Drug and siRNA Using Grapefruit-Derived Nanovectors.

BACKGROUND/AIMS: Multidrug resistance (MDR) is the most common cause of chemotherapy failure. Upregulation of P-glycoprotein (P-gp) is one of the main mechanisms underlying MDR. METHODS: In this study, we developed a targeted drug and small interfering (si)RNA co-delivery system based on specific aptamer-conjugated grapefruit-derived nanovectors (GNVs) that we tested in MDR LoVo colon cancer cells. The internalization of nanovectors in cancer cells was tested by fluorescence microscopy and flow cytometry. The anti-cancer activity in vitro was determined by colony formation and cell apoptosis assays. The biodistribution of nanovectors was analyzed by live imaging and the anti-cancer activity in vivo was observed. RESULTS: GNVs loaded with aptamer increased doxorubicin (Dox) accumulation in MDR LoVo cells, an effect that was abolished by pretreatment with DNase. The LA1 aptamer effectively promoted nanovector internalization into cells at 4°C and increased the targeted delivery of Dox to tumors. Constructs harboring Dox, LA1, and P-gp siRNA more effectively inhibited proliferation and enhanced apoptosis in cultured MDR LoVo cells while exhibiting more potent anti-tumor activity in vivo than free Dox or GNVs loaded with Dox alone or in conjunction with LA1, an effect that was associated with downregulation of P-gp expression. CONCLUSION: This GNV-based system may be an effective strategy for overcoming MDR in clinical settings.

Development of a Specific Aptamer-Modified Nano-System to Treat Esophageal Squamous Cell Carcinoma.

Esophageal squamous cell carcinoma (ESCC) is a prevalent gastrointestinal cancer characterized by high mortality and an unfavorable prognosis. While combination therapies involving surgery, chemotherapy, and radiation therapy are advancing, targeted therapy for ESCC remains underdeveloped. As a result, the overall five-year survival rate for ESCC is still below 20%. Herein, ESCC-specific DNA aptamers and an innovative aptamer-modified nano-system is introduced for targeted drug and gene delivery to effectively inhibit ESCC. The EA1 ssDNA aptamer, which binds robustly to ESCC cells with high specificity and affinity, is identified using cell-based systematic evolution of ligands by exponential enrichment (cell-SELEX). An EA1-modified nano-system is developed using a natural egg yolk lipid nanovector (EA1-EYLNs-PTX/siEFNA1) that concurrently loads paclitaxel (PTX) and a small interfering RNA of Ephrin A1 (EFNA1). This combination counters ESCC's proliferation, migration, invasion, and lung metastasis. Notably, EFNA1 is overexpressed in ESCC tumors with lung metastasis and has an inverse correlation with ESCC patient prognosis. The EA1-EYLNs-PTX/siEFNA1 nano-system offers effective drug delivery and tumor targeting, resulting in significantly improved therapeutic efficacy against ESCC tumors. These insights suggest that aptamer-modified nano-systems can deliver drugs and genes with superior tumor-targeting, potentially revolutionizing targeted therapy in ESCC.

Folic acid conjugated palygorskite/Au hybrid microgels: Temperature, pH and light triple-responsive and its application in drug delivery.

Herein, folic acid conjugated poly (NIPAM-co-functional palygorskite-Au-co-acrylic acid) (FA-PNFA) hybrid microgels were fabricated by emulsion polymerization. The introduction of acrylic acid can increase the low critical solution temperature (LCST) of FA-PNFA from 36 °C at pH 5.5-42 °C at pH 7.4. Doxorubicin hydrochloride (DOX) was chosen as the load drug, the results show that the DOX release behavior is driven by temperature, pH and light. Cumulative drug release rate can reach 74 % at 37 °C and pH 5.5 while only 20 % at 37 °C and pH 7.4, which effectively avoided the early leakage of the drug. In addition, by exposing FA-PNFA hybrid microgels to laser irradiation, the cumulative release rate was increased by 5 % compared to the release rate under dark conditions. Functional palygorskite-Au as physical crosslinkers not only improves the drug loading content of microgels but also promotes the release of DOX through light drive. Methyl thiazolyl tetrazolium bromide (MTT) assay demonstrated that the FA-PNFA are nontoxic up to 200 µg mL-1 towards 4T1 breast cancer cell. Meanwhile, DOX-loaded FA-PNFA show more significant cytotoxicity than the free DOX. Confocal laser scanning microscope (CLSM) revealed that the DOX-loaded FA-PNFA could be efficiently taken by 4T1 breast cancer cells. FA-PNFA hybrid microgels not only improve the LCST of PNIPAM, but also endow the microgels with photostimulation responsiveness, which can release drugs in response to the triple stimulation response of temperature, pH and light, thus effectively reducing the activity of cancer cells, making them more promising for wider medical applications.

LPCAT1 reprogramming cholesterol metabolism promotes the progression of esophageal squamous cell carcinoma.

Tumor cells require high levels of cholesterol for membrane biogenesis for rapid proliferation during development. Beyond the acquired cholesterol from low-density lipoprotein (LDL) taken up from circulation, tumor cells can also biosynthesize cholesterol. The molecular mechanism underlying cholesterol anabolism in esophageal squamous cell carcinoma (ESCC) and its effect on patient prognosis are unclear. Dysregulation of lipid metabolism is common in cancer. Lysophosphatidylcholine acyltransferase 1 (LPCAT1) has been implicated in various cancer types; however, its role in esophageal squamous cell carcinoma (ESCC) remains unclear. In this study, we identified that LPCAT1 is highly expressed in ESCC and that LPCAT1 reprograms cholesterol metabolism in ESCC. LPCAT1 expression was negatively correlated with patient prognosis. Cholesterol synthesis in ESCC cells was significantly inhibited following LPCAT1 knockdown; cell proliferation, invasion, and migration were significantly reduced, along with the growth of xenograft subcutaneous tumors. LPCAT1 could regulate the expression of the cholesterol synthesis enzyme, SQLE, by promoting the activation of PI3K, thereby regulating the entry of SP1/SREBPF2 into the nucleus. LPCAT1 also activates EGFR leading to the downregulation of INSIG-1 expression, facilitating the entry of SREBP-1 into the nucleus to promote cholesterol synthesis. Taken together, LPCAT1 reprograms tumor cell cholesterol metabolism in ESCC and can be used as a potential treatment target against ESCC.

Aptamer-conjugated and doxorubicin-loaded grapefruit-derived nanovectors for targeted therapy against HER2+ breast cancer.

Increased human epidermal growth factor receptor 2 (HER2) expression is a hallmark of HER2+ breast cancer. HER2 promotes the growth of cancer cells and makes them particularly aggressive. Currently, trastuzumab is the only HER2-targeted therapeutic agent approved by the FDA for HER2-overexpressing breast cancer treatment. However, clinical efficacy of trastuzumab is limited greatly by the occurrence of drug resistance. In this study, an aptamer (HA1) specific for HER2-overexpressing breast cancer cells was selected using Cell-SELEX. This allowed the development of grapefruit-derived nanovectors (GNVs) conjugated with HA1 that targeted specifically HER2+ breast cancer cells. In vitro experiments demonstrated that HA1 effectively promoted the internalisation of GNVs into cancer cells and tumour spheroids. In vivo data showed that drug delivery to tumour tissues and antitumor activities were dramatically enhanced by conjugating HA1 with drug-loaded GNVs. This study indicates that aptamers mediating targeted drug delivery by GNVs represent a promising strategy for HER2+ breast cancer therapy.

Enhanced Antitumor Efficacy of Macrophage-Mediated Egg Yolk Lipid-Derived Delivery System Against Breast Cancer.

BACKGROUND: Chemotherapy is the primary treatment for most cancers apart from surgery. However, the use of chemotherapeutic drugs is limited by side effects and restricted accumulation in tumors because of unique tumor microenvironments. Macrophages have excellent drug delivery potential owing to their chemotaxis and can home in on tumors. MATERIALS AND METHODS: We developed an effective drug-delivery system for doxorubicin using macrophages. Doxorubicin-loaded egg yolk lipid-derived nanovectors (EYLNs-Dox) were prepared, EYLNs-Dox-loaded macrophages (Mac/EYLNs-Dox) were developed and their tumor penetration and anti-cancer activity against 4T1 cells were analyzed. The biodistribution and anti-4T1 breast cancer activities were determined using 4T1 subcutaneous and lung metastasis models. RESULTS: EYLNs-Dox was successfully internalized into macrophages without affecting their viability and was less toxic than Dox. Mac/EYLNs-Dox penetrated the 4T1 tumor spheroids more efficiently and was more effective in inhibiting tumors in vitro. Macrophages significantly enhanced the distribution of EYLNs vectors in both inflammatory and tumor sites, playing a more effective role in the inhibition of tumors. CONCLUSION: EYLNs-Dox can be effectively delivered using macrophages and Mac/EYLNs-Dox might be a promising targeted delivery system for breast cancer.

Nanovector Assembled from Natural Egg Yolk Lipids for Tumor-Targeted Delivery of Therapeutics.

Nanomedicine uses nanotechnology-based strategies for precision tumor therapy, including passive and ligand-mediated active tumor targeting by nanocarriers. However, the possible biotoxicity of chemosynthetic nanovectors limits their clinical applications. A novel natural egg yolk lipid nanovector (EYLN) was developed for effective loading and delivery of therapeutic agents. Lipids were extracted from egg yolks and reassembled into nanosized particles. EYLNs' stability, cellular uptake, toxicity, and delivery capacity for therapeutic agents were evaluated in vitro. The systemic toxicity and biodistribution of EYLNs were analyzed in normal mice, and the therapeutic effects of doxorubicin (Dox)-loaded EYLNs were evaluated in mouse breast cancer and hepatoma models. EYLNs had a particle size of ∼40 nm and a surface ζ-potential of -45 mV and were effectively internalized by tumor cells, without showing toxicity and side effects in vitro and in vivo. Importantly, their excellent permeability and retention effect significantly enhanced the distribution of EYLNs at tumor sites, and EYLN-Dox effectively inhibited the tumor growth in both mouse models. Targeted modification with folic acid further promoted vector-mediated drug distribution in tumors. This study demonstrates that lipids with specific proportions in the egg yolk can be used to construct natural drug vectors, providing a new strategy for nano-oncology research.

Leukocyte-Mediated Combined Targeted Chemo and Gene Therapy for Esophageal Cancer.

Poor prognosis of esophageal cancer is associated with limited clinical treatment efficacy and lack of targeted therapies. With advances in nanomedicine, nanoparticle drug delivery systems play increasingly important roles in tumor treatment by enabling the simultaneous delivery of multiple therapeutic agents. We here propose a novel nanovector for targeted combination gene therapy and chemotherapy in esophageal cancer. A novel lipid nanovector (EYLN) was designed to carry the chemotherapy drug doxorubicin (Dox) and small interfering RNA against the lipid anabolic metabolism gene LPCAT1, which we previously showed to be significantly overexpressed in esophageal cancer tissues, and its interference inhibited the proliferation, invasion, and metastasis of esophageal cancer cells. This vector, EYLN-Dox/siLPCAT1, was further coated with leukocyte membranes to obtain mEYLNs-Dox/siLPCAT1. The particle size of the coated nanovector was approximately 136 nm, and the surface zeta potential was -21.18 mV. Compared with EYLNs-Dox/siLPCAT1, mEYLNs-Dox/siLPCAT1 were more easily internalized by esophageal cancer cells due to the LFA-1 highly expressed leukocyte membrane coating and showed significant inhibition of the proliferation, migration, and metastasis of esophageal cancer cells, along with their LPCAT1 expression, through more effective delivery of the drugs. Moreover, the nanovectors showed improved blood circulation time, tissue distribution, tumor targeting, and tumor suppression in a mouse model. Thus, combining chemo and gene therapy with this new nanodelivery system achieved greater therapeutic efficacy, providing a new strategy for the treatment of esophageal cancer.

Mitotic checkpoint kinase Mps1/TTK predicts prognosis of colon cancer patients and regulates tumor proliferation and differentiation via PKCα/ERK1/2 and PI3K/Akt pathway.

Mps1/TTK plays an important role in development of many tumors. The purpose of the present study was designed to investigate the role of TTK in colon cancer. We analyzed TTK and colon cancer in the GEO database, colon cancer tissues and normal tissues were collected to verify the results by immunohistochemistry. We detected the TTK expression in the colon cancer cell lines, and overexpressed or silenced TTK expression in colon cancer cell lines. GEO database showed that the expression of TTK was higher in the colon cancer tissues than normal tissues, higher level of TTK shows unfavourable prognosis in colon patients. Furthermore, high differentiation of colon shows the lower expression of TTK. The higher expression of TTK links with the high microsatellite status. However, the expression of TTK has no significant difference among the different stages of colon cancer patients, and has no significant relationship with recurrence or relapse. Here, we also report that the differential expression of TTK in colon cancer cells alters the intrinsic negative regulation of cell proliferation and differentiation, resulting in the difference of proliferation and differentiation capacity. TTK could activate the PKCα/ERK1/2 to influence the proliferation and inactivate the PI3K/AKT pathway to inhibition the expression of MUC2 and TFF3 that related to the differentiation of colon cells. In conclusions, TTK promote the colon cancer cell proliferation via activation of PKCα/ERK1/2 and inhibit the differentiation via inactivation of PI3K/Akt pathway. TTK inhibition may be the potential therapeutic pathway for the treatment of colon cancer.